Ready to upgrade your old fireplace to one that is more efficient and convenient? Fireplace inserts are perfect for homeowners who have a traditional fireplace but are looking for something with more features. The options are almost endless. Choose from wood-burning, pellet, gas, or electric models in a range of styles and sizes.
- Superior direct vent gas fireplace
Here's a comprehensive overview of what is available and how to choose the right insert for your home. We'll even cover brand recommendations and maintenance tips.
What is a Fireplace Insert?
A fireplace insert is a closed-combustion firebox that is installed into an existing fireplace to increase efficiency. Inserts are usually designed for existing masonry fireplaces, although some manufactured fireplaces accept inserts. There are several categories to choose from depending on the type of fuel you wish to use.
Inserts are available for burning wood (or wood pellets) or for burning gas. Gas inserts can be direct vent, natural vent or vent-free. Almost all inserts come with a blower, though for some, it is an optional addition.
Note that a prefabricated zero clearance fireplace is not the same as a fireplace insert. Zero clearance fireplaces are meant to be framed into a wall or mantel cabinet. Fireplace inserts require an existing fireplace.
Occasionally, you will find a fireplace insert model that is capable of being installed in either a framed opening or an existing fireplace. However, for our purposes, we will use the term " fireplace insert" to refer only to an appliance that installs within an existing fireplace.
Types of Fireplace Inserts
Fireplace inserts are often categorized by the type of fuel they burn. You can choose from wood burning, pellet, natural gas, propane gas, or electric models. The fuel type determines your venting options, as well as the overall operation of the insert. For gas fireplace inserts, you can choose from vent-free, direct vent, and natural vent options.
- US Stove Corn and Pellet-Burning Fireplace Insert
Fireplace Inserts vs. Traditional Fireplaces
One of the main advantages of fireplace inserts is that they offer better heating efficiency. Traditional, open-faced fireplaces are not very efficient when it comes to heating a room. Fireplace inserts are designed to burn fuel better and maximize the heat that radiates to the room. Less fuel is wasted, and less heat is lost to the chimney.
Their high-efficiency design cuts down on fuel and utility costs. They also offer better air quality because little to no smoke is released back into the room.
- Empire Direct Vent Gas Fireplace Insert
Another bonus is that they do not take up additional floor space. Instead, they upgrade a fireplace you already have. Depending on the type of insert, you can install them almost anywhere. Many models are rated for bedrooms and bathrooms and even mobile homes.Though, there are a few other issues to consider.
For one, the sealed front of the inserts somewhat limits flame visibility. They also require an existing fireplace and tend to be smaller in size. Also, although there are a few more modern styles, most of the options are limited to a traditional aesthetic.
If you want big, open, crackling flames or the ability to put a fireplace anywhere you want, an insert is not the best option. However, fireplace inserts are perfect if you are looking to upgrade your existing fireplace or simply want a replacement that is versatile, low maintenance, and more efficient.
How to Choose the Right Fireplace Insert
There are three main considerations when choosing a fireplace insert: the size of the existing fireplace, the type of fuel you want, and your venting preferences. Once you outline your preferences and limitations in those three categories, you'll have a much clearer idea of what model will work best for you.
Measure the Size of Your Existing Fireplace
- White tape measurer
Start by measuring the dimensions of the existing fireplace. This includes measuring the width and height at both the front and back of the fireplace. Sometimes fireplace openings are tapered, meaning the opening at the front is bigger than the width and height of the back of the fireplace. You'll also need to measure the depth of the fireplace.
- Measuring for a fireplace insert infographic
Fireplace inserts are designed to fit inside a range of fireplace sizes. They come with a metal surround that acts as a frame and covers the gap between the insert and the opening of the fireplace. If the opening is too small, the insert will not fit. If the opening is too large, the surround will not be wide enough to cover the gap between the fireplace insert and the opening of the existing fireplace.
Most fireplace inserts are designed for traditional masonry fireplaces (i.e. fireplace openings made out of masonry materials like stone or brick). Finding an insert for a manufactured fireplace is more difficult. Many manufacturers forbid the use of fireplace inserts with their fireplaces, or they limit the inserts to certain approved prefabricated models.
Take note of any other aspects of the existing fireplace. Is it on an outside wall? Does it have a functional chimney? This will help you know your limitations when you move on to the next step of choosing the right fuel.
Choose Your Fuel and Vent Type
Fuel options for your fireplace insert include wood burning, pellet burning, natural or propane gas, and electric. The fuel you use will determine whether you need gas lines or power outlets. It also determines the venting and other installation requirements your insert will need.
Wood Burning Fireplace Inserts
Wood burning fireplace inserts function like a wood stove. They use a flexible or rigid vent liner that routes into the existing chimney. Flexible venting is the most commonly selected method for wood burning inserts and must be a minimum grade of 304 stainless steel, with 316 stainless being preferred.
Flexible liners must meet the requirements of the insert manufacturer and be rated to the UL1777 standard. Typical flexible liner installations will consist of a rigid appliance adapter with a separate or integral gear clamp, the flexible liner itself, a top support plate with clamp, and a cap and storm collar.
The other installation type for wood burning insert venting is rigid liners. While more costly, the rigid liner sections are typically factory insulated and seal very well. The sections will either screw together or utilize a lance and dimple system. Quite literally, think of how a Swiffer mop assembles; you match the two pieces together, slide one into the other and twist to lock it in.
Even if the system does utilize the twist and lock system, at least one screw per section should be used to ensure the liner sections do not separate in the event of a rotation of the liner or, even worse, in the event of a chimney fire.Using a rigid chimney liner is a bit more challenging than a flexible liner, as the excess cannot simply be cut off. Exact measurements for each portion of the liner routing must be taken. The liners must also compensate for offsets, narrow areas, and a specialize termination at the top of the chimney.
To summarize, rigid liner systems require more planning than flexible systems, but they eliminate the need for field installed insulation and are more durable than their flexible counterparts.
Many require a liner for the full length of the chimney. Wood burning fireplace inserts are a good option if you wish to continue using wood for fuel but want a more heat efficient appliance. But, they take more effort to operate and maintain than the other fuel options.
- Napoleon EPA Wood Burning Fireplace Insert
Unlike a masonry wood burning fireplace, wood burning stoves and inserts are subject to EPA efficiency standards. Previous EPA regulations specified that stoves must produce less than 4.5 grams of smoke per hour. In May 2020, that number decreased to 2.5 grams per hour. Unfortunately, the cost of making more energy efficient stove drives the final price up significantly.
While wood stove inserts have an edge on efficiency over wood fireplaces, you can't guarantee that having a wood insert will be more cost efficient. The savings of wood over gas heating can vary. If you buy your firewood in the offseason, you will get lower prices for your wood. If you buy the firewood in the season you need it prices may double.
One of the major disadvantages in wood-burning appliances is the rising costs of operating the appliance. From the cost of the unit itself, which has increased a lot as the overall efficiency rating has changed, rising costs of lumber have changed the overall pricing of owning a wood burning stove.
The cost of a wood-burning fireplace insert, including the purchase of the insert, the installation, and the necessary venting, can run from $1,800 to over $6,400. This range is in both the venting and installation costs, as well as the cost of the inserts themselves.
The lower end of the range assumes that the receiving fireplace is in good condition and that the chimney and fireplace need no service before installation. The lower end also assumes that the chimney is the correct height, is roughly 15 feet (of 304 flex liner with crimp seams) in length, and will be easily terminated using no custom parts. The higher end of the range assumes that the fireplace and chimney need some maintenance, the termination might need some custom fabrication, and up to 30-35 feet of 316 alloy liner with welded seams for the chimney.
Pellet Stove Inserts
A pellet fireplace insert functions like a pellet stove, burning small compressed pellets of wood biomass as fuel. In addition to a chimney for the flexible vent liner, pellet inserts also require an electrical power source. The electricity used to power fans and pellet feed augers within pellet fireplace inserts offers some automation and control over the heat output of the fire. Thermostatic controls can be set to maintain the desired temperature range.
- Napoleon 45-Inch Black Pellet Stove Insert
Pellet stove inserts use a flexible vent liner that runs from the vent collar on the unit up through the chimney. We recommend installing a cleanout tee near the flue collar of the insert so that you can clean out the liner without taking apart the entire vent structure.
Pellet inserts are easy to operate, but they require more maintenance than gas or electric models. When compared to the cost of a gas system, pellet heating is a fraction of the price. When compared to wood burning, pellet heating is cleaner-burning and far more efficient than wood or gas heating by a mile.
Pellet fuel is manufactured for the intended purpose of providing efficient heating. It is quality controlled and tested, with the final product being prepackaged bags with a label showing precisely what is inside, so pellet fuel does not offer the variables to consider with even the best wood burning practices. A pellet-burning insert utilizes pellets for fuel, fed to the fire by an automatic auger, as such, they do require electricity to operate. Though, some models have a backup battery feature to allow operation in the event of a power outage. Pellets are harder to find than other fuel sources but are becoming a little more common.
With pellet systems, venting is not as simple as taking a rough measurement of the total height of the chimney, ordering more than needed and simply cutting away what isn't used. This type of venting depends on the liner you choose. If you choose to use chimney liner to vent your pellet insert, they are typically approved to use 4" diameter chimney liner that is stainless steel and listed to UL 1777, which is the same listing for liner used when relining a chimney for use with a wood insert.
If you do choose to go this route, it would be pretty straightforward & involve ordering more than needed and cutting away what you do not use. There are no manufacturer-specific liner brands you have to use, so long as the proper diameter is used, the liner is listed to UL 1777 and is constructed of stainless steel.
If you were to choose a Type PL pellet system, there is no flexible stainless steel liner to cut. Type PL venting is offered with flexible stainless sections, but each end of this liner commonly has a twist lock section for connecting to PL venting with these same twist lock connections. This typically 10' section is just meant to pass through the damper and smoke shelf to reach the vertical chimney where rigid twist lock sections extend to the top of the chimney, so pretty accurate measurements are needed. Adjustable lengths are available to accommodate any measurement.
The cost of a pellet-burning fireplace insert, including the purchase of the insert, the installation and the necessary venting, can run from $3,000 to $5,000. This range is mostly in the installation, due to the electrical needs. The lower end of the range assumes that the existing fireplace and chimney are in good condition and that there is an electrical source nearby. The lower end of the range also assumes that the chimney does not need to be lengthened and that you need only up to a 15 foot run of 3-inch 304 alloy stainless steel chimney liner.
The higher end of the range includes the need for electrical relocation to power the insert, service to the existing fireplace and chimney, and the possibility of an outside air kit to be installed. The higher end of the range also assumes that you would be using up to a 35 foot run of a 4-inch venting system.
Gas Fireplace Inserts
Gas fireplace inserts require a gas line to accept propane or natural gas. If you do not have an existing gas hook up for the fireplace, you will need to hire a professional plumber to run a line for you. Most models also require an electrical power source. Choose from vent-free, direct vent, and natural vent options for venting the appliance.
The cost of a gas fireplace insert, including the purchase of the insert, the installation, and any necessary venting, can run from $1,500 to over $4,500. The cost of gas fireplace inserts can vary wildly due to installation costs.
The lower end of the range assumes that your existing fireplace is in good condition, you already have the gas line to your fireplace, and that you are installing a vent-free unit which won't require any venting components. The upper end of the range assumes a direct vent gas insert that will require a co-linear vent system to be installed, possible custom termination flashing or modifications, as well as routing of a gas line from existing gas infrastructure within the home.
- Real Fyre mSeries Direct Vent Gas Fireplace Insert
We recommend getting a price quote to get an estimate for the costs for running a new gas line or having an existing gas line extended. Make sure the insert you use is designed for the type of gas you intend to use.
If you need more information to help you understand the differences between natural gas and propane, click here to read this article. It explains the differences between the two gases, tells which gas is best for certain situations, and describes the process for converting from one gas to the other.
Vent-free gas models do not need outside venting. Instead, they rely on room air for oxygen and vent the tiny amount of smoke they produce back into the room. Vent-free inserts are convenient, but check to make sure they are allowed where you live since they are restricted in some areas. They are also not recommended for anyone with air sensitivities.
Direct vent gas inserts are completely sealed to the room and only exchange air through the outdoor venting system. This makes them a good option for anyone especially concerned with air quality since none of the smoke produced ever enters the room. Many direct vent gas fireplace inserts have blowers or electronic ignitions that require electricity. So, be sure to check that you have an outlet nearby if you decide to go with a direct-vent option.
Direct vent gas fireplaces use a rigid coaxial vent pipe that features a small pipe within a larger pipe. The small pipe is responsible for venting the exhaust gases and the larger pipe draws in outside air for combustion.
However, a direct vent gas fireplace insert is designed to vent through the chimney of the existing fireplace. Instead of a rigid coaxial pipe, the inserts use two flexible liners called co-linear vent pipes that run side by side up the chimney. One liner draws in air from outside and the other expels the exhaust gases.
Direct vent inserts are also an excellent choice for customers with homes that have been retrofitted with very tight insulation, resulting in a limited amount of oxygen to supply a naturally drafted system. The combustion chamber is sealed with a solid pane of tempered or ceramic glass and, since all combustion air is drawn in from the outdoors and all combustion gases are exhausted to the outdoors, there is zero air exchange with the home.
So if an existing, leaky hearth is causing heating costs to rise, adding a direct vent gas insert can almost eliminate this headache. Direct vent inserts also release minimal emissions into the atmosphere for those who are environmentally conscious and are safe to install in every state and province. Because many of these systems may be operated with a remote, wall switch or thermostat, they are an excellent choice for customers who want convenience and ease of use.
Unlike direct vent gas inserts, natural vent (b-vent) gas fireplace inserts are not sealed to the room. They require a chimney liner for venting much like a traditional wood burning fireplace. Not all models require an electrical outlet, but always check to make sure you have one if it is needed. These units are mostly used for aesthetics since they have tall, beautiful flames but are not very heat efficient.
Electric Fireplace Inserts
Electric fireplace inserts are the most versatile option. They do not require any venting or gas lines and can be installed almost anywhere. The only consideration is the electrical supply. The flame technology of electric models has come a long way in producing a lovely, realistic fire display. The inserts can come with or without a heating component. Click here to learn more detailed information about electric fireplace inserts, including the different types available, the proper ways to install and clean them, and a list of some top manufacturers.
- Dimplex electric fireplace insert
- Kingsman - This manufacturer is notable as a pioneer of gas-fueled fireplaces and inserts in the hearth industry. With modern products featuring exclusively gas-fueled operation, Kingsman fireplace inserts offer considerable customization options at a price that many can afford. In many cases, several decorative overlays, surrounds, and media options are available for a single insert, allowing the consumer to tailor the appliance to their exact needs.
- Napoleon - It's difficult to find a more all-inclusive product line up than Napoleon products. Realizing early on that the best way to build a strong company was to build something for everyone, Napoleon offers inserts in wood burning, gas, electric, and pellet fueled models. All of their models are built to high standards and are constantly evolving and improving based on real-world needs.
- Quadra-Fire - A long-time manufacturer of high-quality hearth products, Quadra-Fire offers consumers a limited, but handsome looking assortment of wood, gas, and pellet fueled inserts. Their products are timeless and built to a level of quality that makes them stand out.
- Dimplex - Unmatched in quality or variety, Dimplex manufactures one of the widest range of electric fireplaces and inserts in the industry. Well-known as an early player in electric fireplace technology, Dimplex continues to lead the industry in electric flame realism. They offer a range of products that can be installed like an insert, giving consumers an alternative to gas and wood-fired options.
- Types of fireplace inserts infographic
How to Install Fireplace Inserts
There are four basic phases of any fireplace insert installation. The first is the planning stage, which involves finding the right model and planning out the installation. The next stage is the prep work to prepare the existing fireplace for the insert. The last two stages are installation and inspection, which involve installing the insert and testing it to make sure it works properly.
Phase I: Planning
- Two male contractors at an installation site
As mentioned in the section on choosing the right insert, finding an appropriately sized unit is key. Depending on the type of fuel you choose, fireplace inserts are designed to fit a range of openings. Whether you choose to install yours into the opening of existing fireplaces or an opening in a framed wall structure, measure the installation location carefully and double-check that the unit you buy will fit. Once you decide on your fuel preference and size limitations, you can begin planning for the venting components and provisions for a gas line installation.
We recommend hiring a professional to run gas lines or install electrical outlets. Ideally, the electrician will install a recessed outlet behind the fireplace insert. This keeps any cords from trailing out from the unit to nearby power outlets. It's usually best to have a power supply on a dedicated circuit, but this is somewhat dependent on the type of appliance.
Purchase all the appropriate venting components, including chimney liners. If you are converting from one fuel supply to the other, buy the conversion parts you will need.
Phase II: Prep Work
- Fireplace prep for insert installation
The prep work involves any fuel conversion and preparation of the existing fireplace. If the fireplace has a damper, you will likely need to remove it to make room for the chimney liner. Masonry fireplace openings often have rough edges that must be smoothed so the surround of the insert can sit flush against the front of the fireplace.
If the fireplace is stone or brick, the edges can be smoothed with a grinder. Don't use a grinder on material that shatters easily (such as slate). Instead, screed a small layer of cement around the opening to create a smooth edge.
Wood to Gas Conversion
Have a plumber install a gas line for the new fireplace insert. The components need for fireplace inserts are slightly different depending on whether they use natural gas or propane. Make sure the model you buy is rated for the type of gas you intend to use. You will likely need a 120-volt power supply as well.
Always read your owner's manual for details on your specific model. The manufacturer will specify what the appliance requires in terms of the power supply, installation restrictions, and maintenance.
Gas to Wood (or Pellet) Conversion
Remove the gas log lighter and seal the gas supply line. This must be done properly to ensure safety. We recommend hiring a professional plumber to remove gas components and seal the gas lines. You will also need to remove the chimney damper and make sure that there is sufficient venting for the wood-burning fire.
A wood stove insert may or may not need a power supply. But, all pellet stove inserts require a power supply to run the fuel auger and blowers.
Wood or Gas to Electric Conversion
Electric fireplace inserts do not need venting, so close off the cchimney flue and damper. Remove any gas lighter or log sets and properly seal off the gas lines. Hire an electrician to install a recessed outlet behind the electric insert to keep the cords hidden. If a recessed outlet is not an option, you can use a nearby outlet.
- Coverting fuel for fireplace inserts infographic
Phase III: Installation
- Two men delivering a shipment
Many fireplace inserts are heavy, so enlist extra help lifting the unit into place. Start by assembling the venting. Hook up any gas lines or power supply to the unit. Fit the insert into place and use the included hardware to mount the surround around the unit. The surround should sit flush to the opening of the fireplace. Don't forget to add new veneer facing around the perimeter of your fireplace opening if the old one no longer works!
Just make sure to read the instructions for your unit before starting the installation. Depending on the type of model, there may be slight variations in the installation.
Phase IV: Inspection
- Gas pressure meter
Inspection is a critical part of ensuring the safety of your new fireplace insert. We'll go over inspection tips for each of the main categories of fireplace inserts. If you have any concerns about how your fireplace insert is operating, do not hesitate to call the manufacturer or one of our NFI Certified technicians.
- Phases of fireplace insert installation infographic
How to Inspect a Fireplace Insert
- Start the initial kindling fire and watch to see that smoke is drawn to the vent liner and does not spill into the room.
- Once fuel logs are added and burning, close the door. Verify that you can control the rate of the burn by adjusting the air control handle between the high and low burn settings.
- During operation, inspect for smoke leaks around the door gasket. Check that the doors close and latch properly.
- If equipped with an outside air kit, test to see if it operates as it should.
- Complete an external inspection of the chimney to make sure smoke is exiting properly and not pooling at the chimney termination.
How To Inspect Pellet Stove Inserts
- When first starting the unit, test the control board to see if the system responds properly.
- Listen to the pellet feed auger. It should sound relatively quiet and consistent.
- Check that the auger is dropping a metered amount of pellets into the burn pot. It should not be over or under-filling the burn pot.
- Monitor the burn pot to see if the igniter is lighting the pellets and combustion air is helping them burn evenly.
- Watch for any smoke leaks from the glass front or the back of the unit.
- Verify that the convection blower cycles on when it should and that heat is being emitted into the room. If the fan has a manual adjustment, check that all the speed settings work.
- There should not be any smoke smell in the home when the unit is operating.
How To Inspect Vented Gas Fireplace Inserts
- During initial use, check that the pilot light ignites and remains stable prior to igniting the main burner.
- Monitor the main burner ignition. The sequence should be controlled and not sudden or violent.
- Watch the flame pattern. Look for burner ports with no flame or overly sooty or blue flames. If the flame pattern appears incorrect, verify the air shutter is set properly. (The manufacturer will have instructions for these adjustments.)
- If equipped with a fan, test the fan to ensure it cycles as it should.
- Gas appliances release an odor that smells like burning paint when they are first used. Odd smells should not linger after the unit has been used for more than 4 hours.
How To Inspect Vent-Free Gas Fireplace Inserts
- Vent-free gas models follow the same inspection rules as vented gas models.
- However, there is an additional step. You'll need to check that the flame is not being blocked by a log and that there are no acrid odors emitting from the unit.
How To Inspect Electric Fireplace Inserts
- Inspect the unit to see that the backlighting and other lighting features work.
- Verify the heating element operates and the fan-forced heat can be felt in the room (if applicable).
- Listen for odd sounds such as clicking or grinding.
- An odor of hot metal will be present initially but should dissipate within an hour.
- Verify the remote and other controls all function as designed.
Fireplace Insert Maintenance Tips
- Vacuuming the firebox with a brush hose
The owner's manual will contain specific instructions for the care and maintenance of your specific model. Wood and pellet fireplace inserts require the most frequent maintenance. Gas and electric models are easier to maintain but should still be cleaned and inspected regularly.
Wood and Pellet
Always use the proper fuel for wood or pellet stoves. Do not burn trash or any unauthorized fuel since this can lead to harmful creosote buildup. Clean out the ash regularly according to the instructions. Schedule a yearly inspection to make sure all of the components are working safely.
If you installed a cleanout tee on your pellet insert, it should be easier to periodically sweep out the vent liner. Simply remove the surround and gently pull the unit forward. Detach the cover of the cleanout tee to sweep the liner.
Vented and Vent-Free Gas Models
Make sure to have the unit inspected each year by a certified professional to make sure everything is in working order. Periodically vacuum the components to prevent dust buildup. Do this gently so you don't damage any parts. The glass can be cleaned with a soft cloth and a water-based cleanser.
Electric models require the least amount of maintenance. Keep an eye on the electrical wires to make sure they are not frayed or chewed. This is especially important if you have rodents near your area. Vacuum the unit to prevent dust from building up on the fan or other components. You can wipe down the glass periodically.
Small, lightweight fireplace inserts are capable of being shipped via small parcel post. Larger units will require LTL carrier shipping. Always inspect the unit as soon as it arrives to check for any damage or missing parts. Contact the manufacturer immediately if you notice anything amiss.
Fireplace inserts breathe new life into old, inefficient fireplaces. Whether you opt for wood-burning, gas, or electric, you can find a model that fits your space and meets your needs. The range of options for fireplace inserts is quite broad. So, focus on your main priorities for your space to help you narrow down what will be the best option.
As always, reach out to us with any questions! Our NFI Certified Technicians are available to help!